In　order　to　study　the　in-plane　shear　mechanism　of　double　steel　plates　and　filled　concrete　composite　wall　and　in-plane　shear　loading-strain　relations,　base　on　the　data　of　in-plane　shear　experiments　of　double　steel　plates　and　filled　concrete　composite　walls　for　seven　nuclear　power　engineering,　the　loading　formula　and　strain　formula　of　composite　wall　was　deduced　in　different　stress　stage　through　the　stress　of　composite　wall　reasonable　simplified　assumptions,　and　the　finite　element　simulation　was　carried　out　for　c　comparison.　The　comparison　results　indicate　that　the　calculation　value　and　FEM　value　agree　well　with　the　experimental　one,　but　the　ultimate　load　of　calculation　value　is　less　than　that　of　experimental　value,　and　the　strain　value　of　the　finite　element　calculation　is　less　than　the　strain　measured　by　the　experiment　when　the　ultimate　load　is　reached.　The　further　analysis　shows　that　the　crack　direction　of　concrete　wall　panels　for　the　ultimate　load　can　be　simulated　in　the　finite　element　analysis,　the　stud　and　the　tie　bar　have　a　certain　impact　on　the　in-plane　ultimate　shear　load,　but　it　is　difficult　to　accurately　simulate　the　boundary　condition　of　the　composite　structure　in　the　finite　element　analysis.　©　2017,　The　Editorial　Board　of　Journal　of　Basic　Science　and　Engineering.　All　right　reserved.